Interface Modification as a Function of TiC Particle Size in a Solid‐State Consolidated TiC–Steel Metal–Matrix Composite

Abstract

The powder metallurgical incorporation of hard phases in steel matrices is an established concept to form a metal–matrix composite (MMC) with excellent mechanical properties. Especially, TiC has been extensively used in a wide variety of steel matrices in the past. While the stability of TiC particles is known to be low during liquid‐phase sintering, the thermodynamic stability during solid‐state consolidation is less investigated. As the reaction of TiC and the associated formation of reaction phases affect its bonding strength. The bonding strength is considered a crucial parameter for crack initiation in tools, it is important to understand the parameters that control this behavior. To this end, herein, the formation of a (Ti,M)C phase in a TiC–steel MMC is shown, modifying the interface of TiC to the steel matrix during solid‐state consolidation. This is corroborated by thermodynamic calculations and by scanning and transmission electron microscopy combined with energy‐dispersive X‐ray spectroscopy showing that (Ti,M)C is enriched with a significant amount of V, Mo, W, and Cr. High‐energy X‐ray diffraction measurements reveal that with larger normalized surface area of the TiC particles, the amount of (Ti,M)C increases in similar consolidation processes, while the M concentration decreases.